Installation Instructions Owner's manual

5
Publication 1794-IN094B-EN-P - April 2004
Programming the 1794-OB8EP and -OB8EPK
If your program automatically checks for fault bits, bits 8
thru 15 of read word 1 must be masked. This is a sample
program for a module at rack address 1, group 0. Add
similiar rungs to your program.
Resetting a Fault on the 1794-OB8EP or -OB8EPK
Faults can be reset 3 ways: press the fault reset button on
the front of the module; or toggle the output reset bit
(write word 1, bit 08); or cycle backplane power.
Using the Reset Button on the 1794-OB8EP or
-OB8EPK
When you press the reset button, the fault indicator for
the faulted output turns off for about 1.2s. After the
delay, the faulted output attempts to turn on. If the
external condition causing the fault is corrected, the
output will remain on, the fault indicator is off, and the
status indicator is on.
Configuring Your 1794-OB8, -OB16, -OB16P and -OB32P Output
Module
You configure your output module by setting bits in the
configuration word (word 3).
Specifications
Surge Current for the 1794-OB8EP and -OB8EPK
Dec. 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Oct. 17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0
Read Not used
Write O
15
O
14
O
13
O
12
O
11
O
10
O
9
O
8
O
7
O
6
O
5
O
4
O
3
O
2
O
1
O
0
Write
1794-OB32P
only
O
31
O
30
O
29
O
28
O
27
O
26
O
25
O
24
O
23
O
22
O
21
O
20
O
19
O
18
O
17
O
16
Where O = Output - O0 corresponds to output 0, O1 corresponds to output 1, etc.
1794-OB8 uses outputs 0-7; 1794-OB16 and -OB16P use outputs 0-15; 1794-OB32P uses outputs 0-31.
MVM
CMP
Source
Mask
Destination
MASKED MOVE
Compare
Expression
N9: < > 0
I:010
FF00
N9:0
O:000
( Out )
This rung turns on output if a fault occurs.
This rung masked bits 8 thru 15.
Specifications - 24V dc 8 Output Module, Cat. No. 1794-OB8
Number of Outputs 8, nonisolated, sourcing
Module Location Cat. No. 1794-TB2, -TB3, -TB3S
On-state Current 1.0mA minimum per channel
500mA maximum per channel
Output Current Rating 4.0A (8 outputs @ 0.5A)
Surge Current 2A for 50ms, repeatable every 2s
Off-state Leakage 0.5mA maximum
On-state Voltage Drop 0.5V dc maximum
Isolation Voltage Tested at 850V dc for 1s between user and system
No isolation between individual channels
Output Signal Delay Off to On - 0.5ms maximum
On to Off - 1.0ms maximum
Flexbus Current 60mA
Power Dissipation 3.3W maximum @ 31.2V dc
Thermal Dissipation Maximum 11.2 BTU/hr @ 31.2V dc
Indicators (field side
indication, logic driven)
8 yellow status indicators
Fusing Module outputs are not fused. Fusing is recommended. If fusing is
desired, you must provide external fusing. Use SAN-O MQ4-800mA fuses
Specifications - 24V dc 8 Output Module, Cat. No. 1794-OB8EP
and -OB8EPK
Number of Outputs 8 (1 group of 8), nonisolated, sourcing
Module Location Cat. No. 1794-TB2, -TB3, -TB3S, -TBN
On-state Current 1.0mA minimum per channel
2A maximum per channel
Output Current Rating Maximum 2A per output, 10A maximum per module (e.g. 8 outputs @
1.25A, 5 outputs @ 2A, or similar combinations totaling 10A or less)
Surge Current 4A for 10ms, repeatable every 3s (see chart)
Off-state Leakage 0.5mA maximum
On-state Voltage Drop 0.2V dc maximum
Isolation Voltage Tested at 850V dc for 1s between user and system
No isolation between individual channels
Output Signal Delay Off to On - 0.5ms maximum
On to Off - 1.0ms maximum
Flexbus Current 73mA
Power Dissipation 5.5W maximum @ 31.2V dc
Thermal Dissipation Maximum 18.8 BTU/hr @ 31.2V dc
Indicators (field side
indication, logic driven)
8 yellow status indicators
8 red fault indicators
Fusing Outputs are electronically fused
01020304050
0
5
10
15
20
Output Minimum Surge Current
Time - ms
Surge Current - A