Configuration of PROFIBUS® DP Master

Double-click on Profibus_Master_x (Profibus_Master) to open the “Profibus_Master” configuration in the editor window:

Most of the parameters are calculated automatically. Click on button Edit parameter values allows changing the parameters manually. Once edited the parameters the button Set optimal values allows the calculation of the optimal values. The button Set default values can be used to revert all parameters to the default values:

Note

All times for the PROFIBUS® parameters are given in bit time [tBit]. The bit time is the result of the reciprocal of the baudrate:

tBit = 1 / baudrate in [bit/s]

The conversion from milliseconds into a bit time is shown in following formula:

tBit = Time in [ms] * baudrate in [bit/s]

The following parameters are available:

Parameter	Default	Value	Meaning	Parameter (Remark 1 Configuration of PROFIBUS® DP Master)
Identification
Station address	1	0…125	The Station Address is the individual device address of the Master device on the bus.	DpParameter -> Station address
Highest station address	126	0…126	The Highest station address is the highest bus address up to which a master searches for another master at the bus in order to pass on the token. This station address must on no account be smaller than the master station address.	DpParameter -> Highest station address
Mode
Auto-Clear mode	Enabled	Disabled	The Master Operation Mode will stay in the mode Operate and the communication to all available Slaves is kept up.	AutoClearSupported
		Enabled	The Masters Operation Mode will change from Operate to Clear and it shuts down the communication to all assigned slaves, if at least 1 slave is not responding within the Data Control Time.
Bus parameters
Baudrate remark 2 Configuration of PROFIBUS® DP Master	1500	9.6 19.2 45.45 93.75 187.5 500 1500 3000 6000 12000	The baudrate is the data transfer speed in [kBit/s]. The baudrate must be set to be the same for all devices on the bus. The result of changing the baudrate is that all other parameters must be recalculated.	DpParameter -> Baudrate
Slot time	300	37.. 65535	Wait for receipt ““ Monitoring time of the sender (requestor) of telegram for the acknowledgement of the recipient (Responder). After expiration, a retry occurs in accordance with the value of Max. telegram retries.	DpParameter -> TSL
Min. TSDR	11	1…65535	This is the shortest time period that must elapsed before a remote recipient (responder) may send an acknowledgement of a received query telegram. The shortest time period between reception of the last bit of a telegram to the sending of the first bit of a following telegram.	DpParameter -> Min. TSDR
Max. TSDR	150	1…65535	This is the longest time period that must elapse before a sender (requestor) may send a further query telegram. Greatest time period between reception of the last bit of a telegram to the sending of the first bit of a following telegram. The sender (requestor, master) must wait at least for this time period after the sending of an unacknowledged telegram (e.g. broadcast only) before a new telegram is sent.	DpParameter -> Max. TSDR
Quiet time	0	0…127	This is the time delay that occurs for modulators (modulator-trip time) and repeaters (repeater-switch time) for the change over from sending to receiving.	DpParameter -> TQUI
Setup time	1	0…255	Minimum period “reaction time” between the receipt of an acknowledgement to the sending of a new query telegram (reaction) by the sender (requestor).	DpParameter -> TSET
Target rotation time	11894	1.. 2 -1 (=16777215)	Pre-set nominal token cycling time within the sender authorization (token) will cycle around the ring. How much time the master still has available for sending data telegrams to the slaves is dependent on the difference between the nominal and the actual token cycling time. The Target rotation time (TTR) is shown in Bit times [tBit] like the other bus parameters. Below the displayed bit time, the Target rotation time is also displayed in [ms]. The default value depends on the number of slaves attached to the master and their module configuration.	DpParameter -> TTR
Gap update factor	10	0…255	Factor for determining after how many token cycles an added participant is accepted into the token ring. After expiry of the time period G*TTR, the station searches to see whether a further participant wishes to be accepted into the logical ring.	DpParameter -> Gap update factor
Max. retry limit	1	1…15	Maximum number of repeats in order to reach a station.	DpParameter -> max. retry limit
Bus monitoring
Data control time	120	1..2:sup:24-1	The Data control time defines the time in [ms] within the Data_Transfer_List is updated at least once. After the expiration of this period, the master (class 1) reports its operating condition automatically via the Global_Control command. The default value depends on the baudrate.	DpParameter -> Data control time
Min slave interval	2000	1…65535	The Min Slave Interval defines the minimum time period between two slave list cycles in [µs]. The maximum value that the active stations require is always given. The default value depends on the slave types.	DpParameter -> min. slave interval
Poll timeout	10		The parameter Poll timeout sets the maximum period of time in [ms] during which the response has to be received.	DpParameter -> Poll timeout
Calculated timing
Tid1 (read-only)	37	37	Tid1 starts after the initiator has received an acknowledgement, answer or a Token telegram. Tid1 = max (T QUI + 2 * TSET + 2 + TSYN , min TSDR) T SYN : This is the minimum time that must be available to each device as a rest condition before it is allowed to accept the start of a query and it is determined at 33 bit times.	-
Tid2 (read-only)	150	150	Tid2 starts after the initiator has send a telegram which is not acknowledged.. Tid2 = max (T:sub:QUI + 2 * T SET + 2 + TSYN , max TSDR ) T SYN: This is the minimum time that must be available to each device as a rest condition before it is allowed to accept the start of a query and it is determined at 33 bit times.	-

Remark 1: PROFIBUS® DP Configuration

The parameters in this column are shown in tab PROFIBUS DP Configuration which is only visible if parameter Show generic device configuration views is activated (open the Options dialog window with menu item Tools -> Options…, parameter is located under section Device editor):

Remark 2: Baudrate Regarding Bit Time and Cable Length

The following table illustrates the correlation of the baudrate, the bit time and the maximum cable length:

Baudrate in [kBit/s]	Bit time [tBit]	Max. cable length in [m]
9.6	104.2 µs	1200
19.2	52.1 µs	1200
31.25	32 µs	1200
45.45	22 µs	1200
93.75	10.7 µs	1200
187.5	5.3 µs	1000
500	2 µs	400
1500	666.7 ns	200
3000	333.3 ns	100
6000	166.7 ns	100
12000	83.3 ns	100