| #!/usr/bin/python | |
| # SRF cavity analog state computer | |
| # Takes in cavity field, forward, and reverse vector measurements | |
| # and computes the cavity detune frequency, decay parameter, and | |
| # power imbalance for the purposes of a tuning loop and quench detector. | |
| # Keeps a history of the previous four cavity field measurements so it | |
| # can get dV/dt. | |
| # Output of this program should be both valid c99 and valid input | |
| # for the scheduler/mapper. | |
| # See the rest of the Digaree infrastructure for details. | |
| from cgen_lib import cgen_init, given, mul, sub, cpx_sub, cpx_mul | |
| from cgen_lib import cpx_scale, cpx_dot, cpx_inv_conj, cpx_mul_conj | |
| from cgen_lib import cpx_mag, set_result, cpx_persist, cpx_copy, cpx_add | |
| cgen_init("cgen_srf.py") | |
| # History of measured cavity voltages, used to compute dV/dt | |
| # Initial values in simulation are read from init.dat or init2.dat. | |
| cpx_persist("v1") | |
| cpx_persist("v2") | |
| cpx_persist("v3") | |
| cpx_persist("v4") | |
| # These lines declare the input variables, | |
| # first six streamed from the radio | |
| given("k_r") # forward | |
| given("k_i") # forward | |
| given("r_r") # reverse | |
| given("r_i") # reverse | |
| given("v_r") # cavity | |
| given("v_i") # cavity | |
| # next eight host-settable | |
| given("beta_r") | |
| given("beta_i") | |
| given("invT") | |
| given("two") # needed by 1/x macro | |
| given("sclr") | |
| given("sclf") | |
| given("sclv") | |
| given("powt") | |
| # Get (still unscaled) derivative | |
| # Implements [-2 -1 0 1 2] FIR | |
| cpx_sub("dv1", "v", "v4", 3) # note multiply-by-4 | |
| cpx_sub("dv2", "v1", "v3", 2) # note multiply-by-2 | |
| cpx_add("dvx", "dv1", "dv2", 3) # note multiply-by-4 | |
| # Result is the amount that V will change in 80*T. | |
| # Including the second-order CIC used to generate input samples, | |
| # this computation has a 3*T group delay. | |
| # State-variable computation of the complex number a, | |
| # yielding detune frequency and decay rate | |
| cpx_inv_conj("x5", "v", 0, 3) | |
| cpx_scale("dvdt", "dvx", "invT", 1) | |
| cpx_mul("x3", "k", "beta", 1, 1) | |
| cpx_sub("x4", "dvdt", "x3", 2) # some evidence this shift should be 1 | |
| cpx_mul_conj("a", "x4", "x5", 2, 2) | |
| set_result("ab", "a_r", "a_i") | |
| # Power balance measure of cavity dissipation; uses magnitudes only | |
| cpx_mag("magr", "r", 0) # reverse | |
| mul("powr", "sclr", "magr", 0) | |
| cpx_mag("magf", "k", 0) # forward | |
| mul("powf", "sclf", "magf", 0) | |
| sub("wgnet", "powf", "powr", 1) # net power transferred by waveguide | |
| cpx_dot("dvsq", "v", "dvx", 2) # 2 * V * dV/dt = d/dt(V^2) | |
| mul("dudt", "dvsq", "sclv", 3) # dU/dt = power to stored energy | |
| sub("diss", "wgnet", "dudt", 1) # est. of dissipation in cold cavity | |
| sub("perr", "diss", "powt", 1) # allow for measurement error | |
| set_result("cd", "diss", "perr") # trigger quench fault if perr > 0 | |
| # Watch these like a hawk: order of execution matters, | |
| # unlike everything else here | |
| cpx_copy("v4", "v3") | |
| cpx_copy("v3", "v2") | |
| cpx_copy("v2", "v1") | |
| cpx_copy("v1", "v") | |