5.0 CONFIGURATION
The 504
is normally delivered configured for 0 - 50 mV = 4 - 20 mA.
5.1
TOOLS AND EQUIPMENT
Phillips
screwdriver
3/32" flat blade screwdriver, VACO 17764 or equivalent
Two 4 1/2 digit DVMs (digital voltmeters)
10 or 100 ohm 1% resistor
Fixed or variable DC power supply or battery (range of 11-30
V dc)
Millivolt source, -60.00 to +160.00 mV
5.2 CALIBRATION
USING AMBIENT TEMPERATURE
Figure 5-1. Calibration Setup
5.2
CALIBRATION PROCEDURE
Refer to Figure 5-3 (Calibration flowchart) and familiarize yourself
with the general procedure to be followed.
- Remove
the four Phillips-head screws from the case top and set aside
the plastic barrier.
- Lift
out the electronics assembly attached to the case lid.
- Setting
aside the case and sealing gasket, pull out the two sealing
plugs which cover the Span and Zero potentiometers (SPOT and
ZPOT). Adjust SPOT five turns clockwise (CW) from the full
counter-clockwise (CCW) position (SPOT and ZPOT are both multi-turn
pots).
NOTE: SPOT
is never used more than 3/4 of the way clockwise, since full clockwise
disconnects the feedback.
- Refer
to Table 5-2 and select the range which comes closest to your
desired Base and Top millivolt levels. Having done this, note
which zero and span jumpers are called out by the table for
the range that you have selected.
- Turn
the transmitter so that the jumper pin-forest is at hand,
and move the push-on jumpers to the positions indicated in
Figure 5-2 for the range chosen in the previous step. Place
unused jumpers in storage positions.
- Refer
to Figure 5-1 and connect the transmitter to the power supply,
millivolt source, current shunt, and millivoltmeter. Greater
calibration stability can be obtained if the electronic assembly
is installed in the case.
- Using
Table 5-1, determine LO-IN, the Base millivolt level.
- Determine
HI-IN, the Top millivolt level.
- Set the
millivolt calibration source to LO-IN and adjust ZPOT for
4.00 mA output current.
- Set the
millivolt calibration source to HI-IN millivolts and note
the output current (generally this will not be 20 mA). This
current level is designated INITIAL TOP (IT).
- Calculate
TOP CORRECT (TC), the corrected output current, with the following
equation (generally this will also not equal 20 mA).
TC =
16 * IT / (IT - 4)
- Adjust
SPOT to obtain TOP CORRECT milliamperes output current.
- Now readjust
ZPOT so that the output reads 20.00 mA.
- Set the
millivolt calibration source to LO-IN millivolts. If the output
current is not 4.00 mA, repeat steps 9 through 14.
- When
calibration is complete, remove the 504 from the calibration
setup, replace the pot sealing plugs, and install the unit
in the case insuring that the four screws are tightened enough
to compress but not flatten the gasket.
EXAMPLE:
Input Range = -10.00 to +30.00 mV
LO Input = -10.00 mV
HI Input = +30.00 mV
Span and Zero Jumpers - See Table 5-1
Calibration steps:
- Set SPOT
to about 3/4 CCW.
- Set millivolt
source to -10.00 mV.
- Adjust
ZPOT to 4.00 mA.
- Set millivolt
source to +30.00 mV.
- Read
current, designated Initial Top (IT).
- Calculate
TC = 16 * IT/(IT-4)mA.
- Adjust
SPOT to obtain Top Correct (TC) current.
- Adjust
ZPOT to obtain 20 mA current.
- Set millivolt
source to -10.00 mV.
- If the
output is not 4.00 mA, retrim starting at Item 3 above.
5.3
PIN ASSIGNMENTS
(Jumper
Pin-forest P1)
Figure 5-2 Jumper Diagram
|
Pin |
Function |
Pin |
Function |
|
P1-1 |
"A" Zero Jumper |
P1-10 |
Input
tempco control |
|
P1-2 |
|
P1-11 |
V ref input |
|
P1-3 |
"B" |
P1-12 |
"E" Span jumper point |
|
P1-4 |
|
P1-13 |
"G" Span jumper point |
|
P1-5 |
"C" |
P1-14 |
Span
jumper common ground |
|
P1-6 |
|
P1-15 |
Zero
pot wiper (Input high) |
|
P1-7 |
"D" |
P1-16 |
"F"
Span jumper point |
|
P1-8 |
|
P1-17 |
T/C
input low |
|
P1-9 |
Preamp divider center |
P1-18 |
Preamp regulated supply voltage |
Table 5-1 Span Ranges In Millivolts
Obtained With Jumpers
|
WITHOUT
SPAN JUMPERS
|
USING
SPAN JUMPER 'E'
|
|
Z
JUMPERS
|
Adjustable
Range (mV)
|
Z
JUMPERS
|
Adjustable
Range (mV)
|
|
|
Base
|
Top
|
|
Base
|
Top
|
|
NONE
|
-35
|
15
to 55
|
NONE
|
-35
|
-20
to 10
|
|
D
(ONLY)
|
-30
|
20
to 60
|
D
(ONLY)
|
-35
|
-20
to 15
|
|
C
(ONLY)
|
-25
|
40
to 65
|
C
(ONLY)
|
-30
|
-15
to 20
|
|
C
AND D
|
-25
|
45
to 75
|
C
AND D
|
-25
|
-10
to 25
|
|
B
(ONLY)
|
-20
|
50
to 80
|
B
(ONLY)
|
-20
|
-5
to 30
|
|
B
AND D
|
-15
|
55
to 85
|
B
AND D
|
-15
|
0
to 35
|
|
B
AND C
|
-10
|
60
to 90
|
B
AND C
|
-10
|
5
to 40
|
|
B,
C AND D
|
-5
|
65
to 95
|
B,
C AND D
|
-5
|
10
to 45
|
|
A
(ONLY)
|
0
|
70
to 100
|
A
(ONLY)
|
0
|
15
to 50
|
|
A
AND D
|
5
|
75
to 105
|
A
AND D
|
5
|
20
to 55
|
|
A
AND C
|
10
|
80
to 110
|
A
AND C
|
10
|
25
to 60
|
|
A,
C AND D
|
15
|
85
to 110
|
A,
C AND D
|
15
|
30
to 65
|
|
A
AND B
|
25
|
90
to 120
|
A
AND B
|
25
|
40
to 75
|
|
A,
B AND D
|
35
|
95
to 130
|
A,
B AND D
|
35
|
50
to 85
|
|
A,
B AND C
|
45
|
100
to 140
|
A, B AND C
|
45
|
60
to 95
|
|
A,
B, C AND D
|
60
|
105
to 160
|
A, B, C AND D
|
60
|
75
to 110
|
|
USING
SPAN JUMPER 'F'
|
USING
SPAN JUMPER 'G'
|
|
Z
JUMPERS
|
Adjustable
Range (mV)
|
Z
JUMPERS
|
Adjustable
Range (mV)
|
|
|
Base
|
Top
|
|
Base
|
Top
|
|
NONE
|
-35
|
-25
to -10
|
NONE
|
-35
|
-30
to -25
|
|
D
(ONLY)
|
-35
|
-25
to -5
|
D
(ONLY)
|
-35
|
-30 to -20
|
|
C
(ONLY)
|
-30
|
-20
to 0
|
C
(ONLY)
|
-30
|
-25 to -15
|
|
C
AND D
|
-25
|
-15
to 5
|
C
AND D
|
-25
|
-20
to -10
|
|
B
(ONLY)
|
-20
|
-10
to 10
|
B
(ONLY)
|
-20
|
-15
to -5
|
|
B
AND D
|
-15
|
-5 to 15
|
B
AND D
|
-15
|
-10
to 0
|
|
B
AND C
|
-10
|
0
to 20
|
B
AND C
|
-10
|
-5
to 5
|
|
B,
C AND D
|
-5
|
5
to 25
|
B,
C AND D
|
-5
|
0
to 10
|
|
A
(ONLY)
|
0
|
10
to 30
|
A
(ONLY)
|
0
|
5
to 15
|
|
A
AND D
|
5
|
15
to 35
|
A
AND D
|
5
|
10
to 20
|
|
A
AND C
|
10
|
20
to 40
|
A
AND C
|
10
|
15
to 25
|
|
A,
C AND D
|
15
|
25
to 45
|
A,
C AND D
|
20
|
25
to 35
|
|
A
AND B
|
20
|
30 to 50
|
A
AND B
|
30
|
35
to 45
|
|
A,
B AND D
|
30
|
40
to 60
|
A,
B AND D
|
40
|
45
to 55
|
|
A,
B AND C
|
45
|
55
to 75
|
A,
B AND C
|
50
|
55
to 65
|
|
A,
B, C AND D
|
60
|
70
to 90
|
A,
B, C AND D
|
60
|
65
to 75
|
Figure 5-3 Calibration Flowchart
|
|
