Yokogawa GC1000 Mark II Process Gas Chromatograph - Manual (Page 11)

<3. Functions>
3-2
IM 11B06E01-01E
3.3 Alarm information
The conditions of communication with analyzers are mapped as alarm information to the input
relay.
In operation:
This shows that ASGW is accessing the analyzers or PCAS Aalyzer Server specified in the map-
ping file.
Communication failure:
This shows that a time-out error is occurring in communicating with an analyzer. Network line or
analyzer failure may cause the error.
For analyzers connected to PCAS, communication error is indicated by both communication
statuses between ASGW and PCAS or analyzers and PCAS.
Write failure:
It shows that a write error occurs on analyzer. The failure is reset when the next writing succeeds.
PCAS for ARCNET (PCAS/ARC) has multiple virtual analyzer tables, each of which ASGW ac-
cesses.
Alarm information is created for each analyzer, not for the entire PCAS/ARC.
3.4 Modbus interface table
ASGW has the function of Modbus RTU Slave.
This system covers the following function code and number of data with Modbus communication
Modbus interface table
Function Function
Code
BIT/WORD Maximum data by access in one
communication packet.
Read coil status 1 (0x01) BIT 2000 bits
Read input relay status 2 (0x02) BIT 2000 bits
Read holding registers 3 (0x03) WORD 125 words
Read input registers 4 (0x04) WORD 125 words
Write coil 5 (0x05) BIT 1 bit
Write single register 6 (0x06) WORD 1 word
Loopback test 8 (0x08) WORD 1 word
Write multiple coils 15 (0x0F) BIT 800 bits
Write multiple registers 16 (0x10) WORD 100 words
Read devise ID * 43 (0x2B) ASCII string
*: Device ID consists of vendor, product code and revision number.
Vendor : “YOKOGAWA”
Product: ”ASIU”
REVISION: “1.01.01” (example)
Update rate:
ASGW accesses analyzers every 100 ms and supports each read and write request sequentially.
4th Edition : Nov. 22, 2011-00