Aidan. Thomas. Greg. Eric G. Dave H.

Today's work

Flow meter issue

Wired up flow meter. The wiring was 

• Terminal Block on Flow Meter "+" connected to +18V (pin 3) on J10-FEMALE on CO2 controller chassis, D1101835
• Terminal Block on Flow Meter "-" connected to ANALOG IN (pin4) on J10-FEMALE on CO2 controller chassis, D1101835

CO2 Controller Chassis

• Bypassed remote On/Off switch from Beckhoff as this wasn't working. Bypass was done by applying a jumper to Header 2 in D1101835
• Plugged in cable 40X from chiller (shuts down laser if chiller reports a fault)
• Bypassed IR sensor input by applying a jumper
• Plugged in flow meter (shuts down laser if flow drops below 2.5GPM - we checked this. Nominal flow is around 3.5GPM)
• Plugged in laser temperature sensor (shuts down laser if temperature of laser exceeds around 30C). There was a suspicious instantaneous jump in the voltage corresponding to the temperature at the time the laser was turned on (and I mean instanteous, not quick). There was a corresponding drop in the voltage of that channel when the laser current was turned off.

Leaky laser was enabled

Laser (SN 20510.20816D) was run. Maximum output power was 49.4W

Beckhoff issues

CO2 binary outputs not working - traced problem to Beckhoff System Manager not mapping CO2 output hardware to PLC variables.

Plumbing

• Further leak hunting on the table. Moderate leak from main feeds onto the table. About 2 litres of water leaked out onto the corner of the table and the floor. A couple of minor leaks on the manifolds were fixed.
• Installed Laser #3 on the table. This one showed no evidence of leaking from the housing when the chiller was running.

Laser Enable Procedure

It actually takes a large number of ducks to be in a row to turn these CO2 lasers on. So here's how to do it ...

1. Ensure that the laser power cables are connected from the Instek Power Supply (Mech Room) to the CO2X table feedthroughs and, inside the table, connected to the RF driver

2. Mech Room: Turn on the chiller. Check flow rate is approximately 3.5GPM and pressure is abotu 60psi on the chiller. Check that H1:TCS-C_CO2_X_FLOWRATE is about 3.5GPM
3. Mech Room: Turn on Instek power supply. Set output voltage to 29.5V. Set the maximum current to ~28A. Press the enable output button. Check that the current drawn is around 350mA.
4. Mech Room: Turn on the oscillator to 40.68MHz, 11dBm. Ensure the output is connected all the way to the laser table, through the feedthrough and into the Sine-To-TTL box
5. Laser Controller: Ensure all inputs are plugged in.
6. Beckhoff: Set H1:TCS-C_CO2_X_LASERPOWERSWITCH to Valid
7. Laser Table: Ensure the ISS Chassis is turned on
8. Laser Table: Ensure the BO chassis is turned on
9. Laser Controller: Select pulse width modulation (PWM) or continuous wave (CW)
10. If PWM: connect the external controller
11. Laser Controller: (Turn Key off). Turn Key on.
12. Laser Controller: Press the Red Gate ON/OFF button
13. If PWM: turn the dial on the external controller to the desired PWM %.
14. If PWM: press the enable button on the external controller.

The success of this can be gauged by checking:

1. The Instek controller current (H1:TCS-ITMX_CO2_PWR_SUPPLY_I_OUTPUT): should be about 20A at full CW. Or > 1A when laser is running at any power level.  
2. The pick-off on the laser head (H1:TCS-ITMX_CO2_LSRPWR_HD_PD_OUTPUT) should rise to about 45-50W (if calibrated correctly).
3. The temperature of the laser (H1:TCS-C_CO2_X_LASERTEMPERATURE) should increase to about 23-24C