Protocol Type 3964; Protocol: Modbus-Rtu; Notes; Unigate - DEUTSCHMANN AUTOMATION UNIGATE CL-Fast Ethernet Instruction Manual

Deutschmann Automation GmbH & Co. KG

10.3.4 Protocol type 3964

The difference to protocol type 3964R is:
1. tq = acknowledge monitoring time
2. The checksum byte BCC is missing.

10.4 Protocol: MODBUS-RTU

10.4.1 Notes

 For reasons of simplicity, "MODBUS-RTU" is referred to as "MODBUS" in the text below.
 The terms "input" and "output" are always viewed from the gateway's point of view,
i.e. fieldbus input data is the data sent by the fieldbus Master to the gateway.
®

10.4.2 UNIGATE

10.4.2.1 Preparation

Before data exchange is commenced, the parameters "Baud rate", "Parity", "Start bits", "Stop
bits" and "Data bits" and, if applicable, the "Trigger byte" and the "Length byte" must be set.
In addition, a "Response time" which corresponds to the maximum time up to which the Modbus
Slave responds after a request must be set. UNIGATE
ATE by 10 ms.
The user can choose whether the fieldbus requests are forwarded to the Modbus in an
event-driven way (On Event) or on request (On Trigger).
The mode "Modbus request on demand" necessitates the first byte in the fieldbus containing a
trigger byte (see chapter 10.5). This byte is not transferred to the Modbus and serves only to
start a Modbus transmission. For this purpose, the gateway constantly monitors this trigger byte
and sends data to the Modbus only when this byte has changed. In the reverse direction (to the
fieldbus), the gateway transfers the number of received Modbus data records in this byte, i.e. this
byte is incremented by the gateway after each data record.
If the "Length byte" is activated (see chapter 10.6), the gateway transfers only the number of
bytes specified there. The number of received Modbus data items is saved in the direction of the
fieldbus Master. The length always refers to bytes "Address" to "Dat n" (inclusive in each case),
always without CRC checksum.

10.4.2.2 Data structure

21.6.18 UNIGATE
Implemented protocols in UNIGATE® CL with Universal Script

as MODBUS-Master

Fieldbus Gateway UNIGATE
®
®
multiplies the value entered in WING-
CL - Fast Ethernet V. 2.6
®
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