A4.19 Example Of Block Connections; A4.19.1 View Object For Pid Function Block - YOKOGAWA vigilantplant EJA Series User Manual

A4.19 Example of Block Connec-
tions
AI
OUT
IN
PID
BKCAL_IN
CAS_IN
AO
BKCAL_OUT
FA0406.EPS
When configuring a simple PID control loop by
combining an EJA transmitter with a fieldbus valve
positioner that contains an AO block, follow the
procedure below to make the settings of the corre-
sponding fieldbus function blocks:
1. Connect the AI block and PID block of the EJA,
and the AO block of the valve positioner as shown
above.
2. Set MODE_BLK.target of the PID block to O/S,
and then set GAIN, RESET, and RATE to appropri-
ate values.
3. Check that the value of MODE_BLK.actual of the
AI block is Auto.
4. Set MODE_BLK.target of the AO block to
CAS|AUTO (meaning "Cas and Auto").
5. Check that the value of BKCAL_IN.status of the
PID block is not Bad.
6. Check that the value of IN.status of the PID block is
not Bad.
7. Check that Auto is set in MODE_BLK.permitted of
the PID block.
8. Set MODE_BLK.target of the PID block to Auto.
When finishing all steps in order, the PID block and
AO block exchange the respective information and
initialize the cascade connection. Consequently, the
value of MODE_BLK.actual of the PID block changes
to Auto and automatic PID control starts.
OUT
A4.19.1 View Object for PID Function
Block
Relative
Parameter Mnemonic
Index
1 ST_REV
2 TAG_DESC
3 STRATEGY
4 ALERT_KEY
5 MODE_BLK
6 BLOCK_ERR
7 PV
8 SP
9 OUT
10 PV_SCALE
11 OUT_SCALE
12 GRANT_DENY
13 CONTROL_OPTS
14 STATUS_OPTS
15 IN
16 PV_FTIME
17 BYPASS
18 CAS_IN
19 SP_RATE_DN
20 SP_RATE_UP
21 SP_HI_LIM
22 SP_LO_LIM
23 GAIN
24 RESET
25 BAL_TIME
26 RATE
27 BKCAL_IN
28 OUT_HI_LIM
29 OUT_LO_LIM
30 BKCAL_HYS
31 BKCAL_OUT
32 RCAS_IN
33 ROUT_IN
Subtotals
A-22
APPENDIX 4. PID Block
VIEW VIEW VIEW VIEW
1 2 3 4
2 2 2 2
2
1
4 4
2 2
5 5
5 5
5 5
11
11
2
2
2
5
4
1
5 5
4
4
4
4
4
4
4
4
5
4
4
4
5
5
5
28 43 53 41
TA0413-1.EPS
IM 01C22T02-01E